MacBook Pro screen turning off and on unless plugged into external display or playing video

This sounds like a hardware issue. I would suggest changing the display settings without the monitors or any peripherals connected to the device. That way you would illuminate any issues of contamination from other devices. I’d also do a hard shut down instead of resetting. And if that issue persists I would treat a guest account or login to the guest user account and Test and see if the problem still persists. If he does after changing display settings then I would suggest scheduling a genius bar appointment

User_Wolfgang Said:

"MacBook Pro screen turning off and on unless plugged into external display or playing video: [...]This problem occurred a while ago and it went away when I updated it to Big SurOS. This problem has returned and I have tried updating it again to the now current MontereyOS 12.4. However this problem still persists.[...]"

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Reinstall the macOS:

Nothing would be lost. It's just that misplaced items would be placed back to where they should be and corrupt system files would be replaced by clean files. Go Here: Reinstall macOS - Apple Support. Use the third bulleted method: [command + r]. Important: Prior to installing an update or performing a reinstallation, to prevent data loss, be sure to Back up your Mac with Time Machine. Report back if that fixes this.